1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a mounting circuit board thereof.
2. Description of the Related Art
Since a multilayer ceramic capacitor (MLCC), one of multilayer chip electronic components, has advantages such as a small size, high capacitance, easiness of mounting, and the like, the multilayer ceramic capacitor may be used in various electronic devices.
For example, a multilayer ceramic capacitor may be used as a chip type condenser mounted on circuit boards of various electronic products such as display devices including liquid crystal displays (LCDs), plasma display panels (PDPs), and the like, computers, personal digital assistants (PDAs), and mobile phones to serve to charge or discharge electricity.
Generally, the multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having opposite polarities and interposed between the dielectric layers are alternately laminated.
In this case, since the dielectric layers have piezoelectricity, when direct current (DC) or alternating current (AC) voltage is applied to the multilayer ceramic capacitor, a piezoelectric phenomenon is generated between the internal electrodes, thereby generating periodic vibrations while expanding and contracting the volume of a ceramic body according to frequency.
Such vibrations may be transferred to a circuit board through external electrodes of the multilayer ceramic capacitor and a solder connecting the external electrodes to the circuit board, such that the entire circuit board may become an acoustically reflective surface to generate a vibration sound as noise.
This vibration sound may correspond to an audible frequency range of 20 to 20,000 Hz making listeners uncomfortable. The vibration sound, potentially providing unpleasant feeling to listeners, is known as acoustic noise.
Recently, since acoustic noise generated in the multilayer ceramic capacitor as described above maybe evident due to noise reductions in components of electronic devices, research into a technology for reducing the acoustic noise generated in the multilayer ceramic capacitor has been required.
As a method of reducing the acoustic noise as described above, a method of mounting a multilayer ceramic capacitor so as to be spaced apart from a circuit board by a predetermined distance using a metal frame has been disclosed.
However, in order to reduce the acoustic noise to a predetermined level using the metal frame, a distance between the metal frame and the circuit board should be increased to be greater than a predetermined standard distance.
In addition, since the above-described distance increase between the metal frame and the circuit board results in an increase in a height of a product in which the multilayer ceramic capacitor is mounted, it may be difficult to use the metal frame in a set having a height limitation.
A method of reducing acoustic noise transferred from a multilayer ceramic capacitor to a circuit board using a metal terminal is disclosed in the following Patent Document 1, but a method of reducing a size of a product is not disclosed therein.